‘Redock Dark’ is a product of a breeding and selection program which had the objective of finding color mutants of ‘Redock’. The new plant of the present invention comprises a new and distinct cultivar of chrysanthemum plant that is a natural occurring sport of a parent chrysanthemum named ‘Redock’ (unpatented). A comparison with parent chrysanthemum ‘Redock’ is also made in this application. The new cultivar was discovered as a whole plant mutation in September, 1999 by Rob Noodelijk in a controlled environment (greenhouse) in Rijsenhout, Holland. The first act of asexual reproduction of ‘Redock Dark’ was accomplished when vegetative cuttings were taken from the initial selection in November, 1999 in Rijsenhout, Holland.